R. D. Labyntsevа¹, O. V. Bevza¹, A. A. Bevza¹, A. M. Lulko¹,
S. Kharchenko², V. I. Kalchenko², S. O. Kosterin¹

¹Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
е-mail: labyntseva@biochem.kiev.ua;  kinet@biochem.kiev.ua;
²Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv;
е-mail: vik@ioch.kiev.ua

Heavy metals have a negative effect on the contractility of uterine smooth muscles (myometrium), these effects can lead to various pathologies of a women reproductive system. To overcome these effects the methods for correcting the myometrium contractile activity are  to be developed. Catalyzed by myosin ATPase ATP hydrolysis is the most important reaction in the molecular mechanism of myo­metrium contraction. We have found an inhibitory effect of 0.03-0.3 mM Ni²⁺, Pb²⁺ and Cd²⁺ on enzymatic hydrolysis of ATP by myosin subfragment-1 obtained from swine uterine smooth muscles. We have demonstrated that 100 µM thiacalix[4]arene-tetrasulphonate (C-798) recovered to the control level of ATPase activity of myosin subfragment-1 in the presence of heavy metal cations. One of the most probable mechanisms of C-798 corrective activity is based on its ability to chelate heavy metals, thus cations Pb, Cd and Ni can be removed from the incubation medium. Computer simulation has demonstrated that the protective effect of C-798 may also be the result of weakening the interaction of heavy metal ions with amino acid residues of the myosin molecule near the active site of ATP hydrolase. The obtained results can be used for further research aimed at assessing the prospects of thiacalix[4]arene-tetrasulfonate as pharmacological compounds.